ABA Online Bird Photo Quiz 131

Answer

The long legs and long toes of this backlit bird suggest that we should be looking among the herons and other heron-like birds for a solution. The perch location rules out cranes and the fairly short and stout bill rules out storks, leaving us with the true herons as the remaining members of the potential solution set. The short and stout bill goes a long way toward whittling down our options, as does the fact that the bird is not white. Yes, it’s backlit, but there’s still enough resolution to see that the bird’s plumage is fairly dark. The reductions in solution-set members enabled by bill size and shape and by overall plumage color should leave us with just Green Heron and the two species of night-heron as viable options. Going back to leg length enables us to rule out the short-legged Green Heron.

Since we can see enough vague suggestions of plumage color to know that a) there are no strong dark-light color-tone contrasts anywhere on the bird and b) there is, in fact, fairly heavy streaking on the underparts, we should be looking for features that would enable us to separate juveniles of these two species. Overall plumage pattern in them is quite similar, with details of the size of white spots on the wing coverts and the presence or absence of whitish leading edges of the greater secondary coverts being particularly useful. Unfortunately, such details are difficult to determine in this poorly-lit picture. Oh, we could do it, but those are not the features that I wanted to elucidate this time ‘round.

In flight, the juveniles of Yellow-crowned and Black-crowned night-herons are differentiated by two particular features, but only one of which works in such poor lighting conditions. That feature is the amount of leg that trails behind the tail, with Yellow-crowneds having more than just toes sticking out the back end. Instead, a little bit of the tarsometatarsus (read, the foot bone proximal to the juncture of all the toes; that is, between the toes and the heel) is visible. This difference in foot projection is not created by a longer foot in Yellow-crowned, but by longer bones above the foot. In fact, this difference is created by the considerably longer tibiotarsus of Yellow-crowned Night-Heron relative to the shorter tibiotarsus in Black-crowned Night-Heron -- roughly equivalent to the shin section of our legs; you do know that that big, knobby joint visible in the picture is effectively the bird’s heel, right? This difference creates a different look on perching/standing individuals of the two species, with extensive leg visible between that joint and the body, whereas Black-crowned Night-Heron shows little or no leg between the joint and the body.

Of course, if you grab the picture and lighten it (see below), the bird’s small covert spots and obvious whitish leading edges to the greater secondary coverts are obvious, supporting our identification by leg length.

I took this picture of a juvenile Yellow-crowned Night-Heron at Smith Point, Chambers Co., TX, on 23 August 2013.

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The following people (listed by submission date beginning with the earliest) submitted correct answers for the December Bird Photo Quiz—Yellow-crowned Night-Heron:

Karl Erich Mayer - Tawas City, Michigan

Christian Schwarz - Santa Cruz, CA

Dan Cowell - Holden, MO

Gabriel Mapel - New Hope, Virginia

Michael David - Altoona, PA

Sunil Gopalan - Madison, WI

Karrin Burns - Oak Park, IL

Nate McGowan - Austin, TX

Anders Ogren - Old Saybrook, CT

David Benson - Macomb, IL

timothy white - providence, ri

Shawn Layton - Princeton, NJ

Marky Mutchler - Liberty, Missouri

Simon Kiacz - Flushing, Michigan

Willy Hutcheson - Concord, MA

Alison Beringer - Bloomfield, NJ

Cal Walters - Piedmont, CA

Michelle ward - Louisville Kentucky

John Dillon - Athens, LA

Claude Auchu - La Pocatiere, Quebec

Mayn Hipp - Boston, MA

Joseph Bourget - Worcester, MA

John Hammond - Durham, NC

Valeri Ponzo - Sarasota, FL

Nathaniel Smith - Prescott, AZ

Jeanne R. Tinsman - Las Vegas, NV

Malcolm Mark Swan - Valparaiso, Florida

Lance Verderame - Livingston Manor, New york

Chris Warren - Makawao, HI

Martin Sharp - Edmonton, Alberta

Dean Nicholson - Cranbrook, B.C.

Laure Neish - Penticton, BC

Bob Proctor - Elgin, Scotland

Marcelo Brongo - Sant Cugat del Valles, Spain

Greg Prelich - Manchester, NJ

Greg Schrott - Avon Park, FL

Matt Brady - Baton Rouge, LA

Josh Southern - Raleigh, NC

Michael Lester - Tucson, AZ

Patty McKelvey - Sheffield Village, Ohio

Gale Diakuw - Osler, Saskatchewan, Canada

Aidan Rominger - Indianapolis

Patrice Domeischel - Setauket, NY

Anya Auerbach - New York, NY

Kai Shaikh - Pittsburgh, Pennsylvania

Samuel Ewing - Gainesville, FL

William Rockey - Esparto, CA

Nina Sitra - Sugar Land, TX

Kent Fiala - Hillsborough, NC

Eric Heisey - Granger, Washington

Joshua Glant - Seattle, WA

Kyle Lima - Ellsworth, Maine

Hayden Bildy - London, ON

Aidan Bodeo-Lomicky - Bethlehem, PA

Robert McNab - Laguna Niguel, CA

Amy Darling - Denver, CO

Chuck Carlson - Ft. Peck, MT

Darrel Wilder - Johnson City, TN

Austin Young - Filer, ID

Donald Lima - Ellsworth, ME

Peter Lane - Québec City, Canada

Hannah Tripp - King George, VA

Michael Kline - Fredericksburg Va.

Kyle Leader - Bainbridge Island, Washington

Justin Jones - Phoenix, AZ

Jon Atwood - Keene, NH

Robert Packard - Riverside, CA

Chloe Walker - Murfreesboro, TN

Elaine Reilly - Belchertown, MA

Alec Olivier - Marquette, Michigan

Andrew Aldrich - Downers Grove, IL

Carl Giometti - Chicago, IL

Jack Holloway - Mesa, AZ

Jonathan Frodge - Cincinnati, OH

Brennan Obermayer - Barrie, ON

Kevin Hill - SHORELINE, WA

Jacob Glazer - Rochester, New York

Zak Pohlen - East Lansing, MI

Gary Woods - Fresno, CA

Joshua Snodgrass - Trumansburg, NY

Tom Ford-Hutchinson - Irvine, CA

Joseph Miller - Nickerson, Kansas

James Telford - Calgary, AB

Danny Tipton - Albuquerque, NM

Hiram Herrera - Chula Vista

Elizabeth Goulet - San Diego

Linda Fink - Grand Ronde, OR

Walter Wehtje - Peterborough, ON

Joe Busse - Palatine, Il

George Cresswell - Colorado Springs, CO

David Hollie - Ringgold, GA

Philip Kline - Portland, OR

Elaine MacPherson - Sierra Made, CA

John Habig - Carlisle, OH

David Dudley - Saint Paul, MN

Margaret Martin - Roseville, CA

Dawn Huss - Encinitas, CA

Cade Cropper - Loveland, CO

Chris Sloan - Nashville, TN

Chris Blazo - Chambersburg, PA

Phil Gerkin - Aurora, CO

Jim Mountjoy - Galesburg, IL

Bob Archer - Portland

Geoff Urwin - Warman, SK

Ed Harper - Carmichael, CA

Anton Mach - Yardley, PA

Terri Everett - Big Rapids, MI

Barb Robertson - Ottawa, Ontario, Canada

Reynold Larsen - Newport RI

Daroczi J. Szilard - Tg.-Mures, Romania

Lucie Bruce - Houston, TX

Georgia Conti - Patzcuaro, Michoacan, Mexico

Celestyn Brozek - Albuquerque, NM

Josiah LaCelle - Camden NY

Don Jones - Middlebury, VT

Greg Zupansic - Eugene, Oregon

James McKay - Mesa, AZ

Sarah Toner - Ann Arbor

Joshua Anderson - Duluth, MN

Sam Fason - Austin, TX

Luke Hollander - Minneapolis, MN

Nick Minor - Libertyville, IL

Bobby Walsh - Davis, CA

Josh Kamp - Marne, MI

Eli Miller - Millersburg Ohio

Caitlin McKinnell - Northampton MA

Michael Rae - Woburn, Ma.

Jim Flynn - Seattle, WA

Abril Heredia - Mexico City

How Did You Compare?

As stated in the quiz rules, answers must consist simply of the Common or English name exactly as it appears in the ABA Checklist.

The following list shows the number of submissions for each species guessed.